SOLUTION: how to find the sum of 50+51+52+...+83+84

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Question 987851: how to find the sum of 50+51+52+...+83+84
Answer by ikleyn(52817) About Me  (Show Source):
You can put this solution on YOUR website!
.
It is an arithmetic progression with the first term  a%5B1%5D = 50,  the common difference  1  and the number of terms is  (84-49) = 35.

Apply the formula for the sum of first  n  terms of an arithmetic progression
(see, for example, the lesson  Arithmetic progressions  in this site).

S = %28a%5B1%5D%2Ba%5Bn%5D%29%2F2%2An%29+=+%7B%7B%7B%2850%2B84%29%2F2%2A35 = %28134%2F2%29%2A35 = 67*35 = 2345.